Achaemenid /əˈkiːmənɪd/adjective 1noun 1forms 2 adjective1 •Of or relating to the dynasty which ruled the Persian empire c. 550–330 BCE (the Achaemenid Empire), founded by Achaemenes. noun1 •A member of the dynasty which ruled the Persian empire c. 550–330 BCE (the Achaemenid Empire). formsAchaemenidae · Achaemenids